The NEI Central Transgenic Animal Facility is a research support facility for all NEI intramural researchers requiring the use of transgenic mice in their research programs. We are currently providing transgenic animal support to researchers from many laboratories/branches in the NEI (LI, LMDB, LMOD, LOT, LRCMB, OGVFB, OSD, LMB[NIDCD]). Our program has handled approximately 280 DNA constructs, which are at various stages of completion. NEI researchers, using molecular biology techniques to study the eye, submit DNA constructs to our section for production of transgenic mice. We create transgenic mice by standard procedures, then biopsy and perform DNA analysis on the mice which are born from these procedures to identify transgene positive mice. At the researchers' request, we mate positive transgenic mice, wean litters, biopsy and analyze DNA from successive generations of transgenic mice, provide the transgenic animals to researchers for use in their experiments, and cryopreserve and bank embryos from important mouse lines (both transgenic and naturally occurring) for long term storage. For generating gene knockout mice, we perform ES cell injections into blastocysts, and this year have collaborated on a knockout project, doing essentially all of the ES cell work. We also help researchers design transgenic projects and transgene/knockout vectors on a collaborative basis. This year we have: * accepted 28 new constructs for transgenic mouse production; * generated 156 transgenic founder mice; * set up 627 matings of transgenic mice; * weaned, tagged and tail biopsied 4,602 mice; * isolated DNA from 6,248 samples; * performed 6,327 PCR analyses; * cryopreserved 2,740 embryos from 7 lines of mice * injected 9 lines of ES cells into blastocysts for generation of knockout mice * generated 19 chimeric mice